<template>
  <div class="ui-select" :class="classes">
    <input
      class="ui-select__hidden-input"
      type="hidden"

      :name="name"
      :value="submittedValue"

      v-if="name"
    >

    <div class="ui-select__icon-wrapper" v-if="icon || $slots.icon">
      <slot name="icon">
        <ui-icon :icon="icon"></ui-icon>
      </slot>
    </div>

    <div class="ui-select__content">
      <div
        class="ui-select__label"
        ref="label"

        :tabindex="disabled ? null : '0'"

        @click="toggleDropdown"
        @focus="onFocus"
        @keydown.enter.prevent="openDropdown"
        @keydown.space.prevent="openDropdown"
        @keydown.tab="onBlur"
      >
        <div
          class="ui-select__label-text"
          :class="labelClasses"
          v-if="label || $slots.default"
        >
          <slot>{{ label }}</slot>
        </div>

        <div class="ui-select__display">
          <div
            class="ui-select__display-value"
            :class="{ 'is-placeholder': !hasDisplayText }"
          >
            {{ hasDisplayText ? displayText : (hasFloatingLabel && isLabelInline) ? null : placeholder }}
          </div>

          <ui-icon class="ui-select__dropdown-button">
            <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M6.984 9.984h10.03L12 15z"/></svg>
          </ui-icon>
        </div>

        <transition name="ui-select--transition-fade">
          <div
            class="ui-select__dropdown"
            ref="dropdown"
            tabindex="-1"

            @keydown.down.prevent="highlightOption(highlightedIndex + 1)"
            @keydown.enter.prevent.stop="selectHighlighted(highlightedIndex, $event)"
            @keydown.esc.prevent="closeDropdown()"
            @keydown.tab="onBlur"
            @keydown.up.prevent="highlightOption(highlightedIndex - 1)"

            v-show="showDropdown"
          >
            <div
              class="ui-select__search"

              @click.stop
              @keydown.space.stop

              v-if="hasSearch"
            >
              <input
                autocomplete="off"
                class="ui-select__search-input"
                ref="searchInput"
                type="text"

                :placeholder="searchPlaceholder"

                v-model="query"
              >

              <ui-icon class="ui-select__search-icon">
                <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24">
                  <path d="M9.516 14.016c2.484 0 4.5-2.016 4.5-4.5s-2.016-4.5-4.5-4.5-4.5 2.016-4.5 4.5 2.016 4.5 4.5 4.5zm6 0l4.97 4.97-1.5 1.5-4.97-4.97v-.797l-.28-.282c-1.126.984-2.626 1.547-4.22 1.547-3.61 0-6.516-2.86-6.516-6.47S5.906 3 9.516 3s6.47 2.906 6.47 6.516c0 1.594-.564 3.094-1.548 4.22l.28.28h.798z"/>
                </svg>
              </ui-icon>

              <ui-progress-circular
                class="ui-select__search-progress"
                :size="20"
                :stroke="4"
                v-show="loading"
              ></ui-progress-circular>
            </div>

            <ul class="ui-select__options" ref="optionsList">
              <template v-for="(option, index) in filteredOptions">
                <ui-select-option
                  ref="options"

                  :highlighted="highlightedIndex === index"
                  :keys="keys"
                  :multiple="multiple"
                  :option="option"
                  :selected="isOptionSelected(option)"
                  :type="type"

                  @click.native.stop="selectOption(option, index)"
                  @mouseover.native.stop="highlightOption(index, { autoScroll: false })"

                >
                  <slot
                    name="option"

                    :highlighted="highlightedIndex === index"
                    :index="index"
                    :option="option"
                    :selected="isOptionSelected(option)"
                  ></slot>
                </ui-select-option>
              </template>

              <div class="ui-select__no-results" v-show="hasNoResults">
                <slot name="no-results">No results found</slot>
              </div>
            </ul>
          </div>
        </transition>
      </div>

      <div class="ui-select__feedback" v-if="hasFeedback">
        <div class="ui-select__feedback-text" v-if="showError">
          <slot name="error">{{ error }}</slot>
        </div>

        <div class="ui-select__feedback-text" v-else-if="showHelp">
          <slot name="help">{{ help }}</slot>
        </div>
      </div>
    </div>
  </div>
</template>

<script>
import UiIcon from './UiIcon.vue'
import UiProgressCircular from './UiProgressCircular.vue'
import UiSelectOption from './UiSelectOption.vue'

import config from './config'
import fuzzysearch from 'fuzzysearch'
import { looseIndexOf, looseEqual } from './helpers/util'
import { scrollIntoView, resetScroll } from './helpers/element-scroll'

export default {
  name: 'ui-select',

  props: {
    name: String,
    value: {
      type: [String, Number, Object, Array],
      required: true
    },
    options: {
      type: Array,
      default () {
        return []
      }
    },
    placeholder: String,
    icon: String,
    iconPosition: {
      type: String,
      default: 'left' // 'left' or 'right'
    },
    label: String,
    floatingLabel: {
      type: Boolean,
      default: false
    },
    type: {
      type: String,
      default: 'basic' // 'basic' or 'image'
    },
    multiple: {
      type: Boolean,
      default: false
    },
    multipleDelimiter: {
      type: String,
      default: ', '
    },
    hasSearch: {
      type: Boolean,
      default: false
    },
    searchPlaceholder: {
      type: String,
      default: 'Search'
    },
    filter: Function,
    disableFilter: {
      type: Boolean,
      default: false
    },
    loading: {
      type: Boolean,
      default: false
    },
    noResults: {
      type: Boolean,
      default: false
    },
    keys: {
      type: Object,
      default () {
        return config.data.UiSelect.keys
      }
    },
    invalid: {
      type: Boolean,
      default: false
    },
    help: String,
    error: String,
    disabled: {
      type: Boolean,
      default: false
    }
  },

  data () {
    return {
      query: '',
      isActive: false,
      isTouched: false,
      selectedIndex: -1,
      highlightedIndex: -1,
      showDropdown: false,
      initialValue: JSON.stringify(this.value)
    }
  },

  computed: {
    classes () {
      return [
        `ui-select--type-${this.type}`,
        `ui-select--icon-position-${this.iconPosition}`,
        { 'is-active': this.isActive },
        { 'is-invalid': this.invalid },
        { 'is-touched': this.isTouched },
        { 'is-disabled': this.disabled },
        { 'is-multiple': this.multiple },
        { 'has-label': this.hasLabel },
        { 'has-floating-label': this.hasFloatingLabel }
      ]
    },

    labelClasses () {
      return {
        'is-inline': this.hasFloatingLabel && this.isLabelInline,
        'is-floating': this.hasFloatingLabel && !this.isLabelInline
      }
    },

    hasLabel () {
      return Boolean(this.label) || Boolean(this.$slots.default)
    },

    hasFloatingLabel () {
      return this.hasLabel && this.floatingLabel
    },

    isLabelInline () {
      return this.value.length === 0 && !this.isActive
    },

    hasFeedback () {
      return Boolean(this.help) || Boolean(this.error)
    },

    showError () {
      return this.invalid && Boolean(this.error)
    },

    showHelp () {
      return !this.showError && Boolean(this.help)
    },

    filteredOptions () {
      if (this.disableFilter) {
        return this.options
      }

      return this.options.filter((option, index) => {
        if (this.filter) {
          return this.filter(option, this.query)
        }

        return this.defaultFilter(option, index)
      })
    },

    displayText () {
      if (this.multiple) {
        if (this.value.length > 0) {
          return this.value
              .map(value => value[this.keys.label] || value)
              .join(this.multipleDelimiter)
        }

        return ''
      }

      return this.value ? (this.value[this.keys.label] || this.value) : ''
    },

    hasDisplayText () {
      return Boolean(this.displayText.length)
    },

    hasNoResults () {
      if (this.loading || this.query.length === 0) {
        return false
      }

      return this.disableFilter ? this.noResults : this.filteredOptions.length === 0
    },

    submittedValue () {
      // Assuming that if there is no name, then there's no
      // need to computed the submittedValue
      if (!this.name || !this.value) {
        return
      }

      if (Array.isArray(this.value)) {
        return this.value
          .map(option => option[this.keys.value] || option)
          .join(',')
      }

      return this.value[this.keys.value] || this.value
    }
  },

  watch: {
    filteredOptions () {
      this.highlightedIndex = 0
      resetScroll(this.$refs.optionsList)
    },

    showDropdown () {
      if (this.showDropdown) {
        this.onOpen()
        this.$emit('dropdown-open')
      } else {
        this.onClose()
        this.$emit('dropdown-close')
      }
    },

    query () {
      this.$emit('query-change', this.query)
    }
  },

  created () {
    if (!this.value || this.value === '') {
      this.setValue(null)
    }
  },

  mounted () {
    document.addEventListener('click', this.onExternalClick)
  },

  beforeDestroy () {
    document.removeEventListener('click', this.onExternalClick)
  },

  methods: {
    setValue (value = '') {
      value = value || (this.multiple ? [] : '')

      this.$emit('input', value)
      this.$emit('change', value)
    },

    highlightOption (index, options = { autoScroll: true }) {
      if (this.highlightedIndex === index || this.$refs.options.length === 0) {
        return
      }

      const firstIndex = 0
      const lastIndex = this.$refs.options.length - 1

      if (index < firstIndex) {
        index = lastIndex
      } else if (index > lastIndex) {
        index = firstIndex
      }

      this.highlightedIndex = index

      if (options.autoScroll) {
        this.scrollOptionIntoView(this.$refs.options[index].$el)
      }
    },

    selectHighlighted (index, e) {
      if (this.$refs.options.length > 0) {
        e.preventDefault()
        this.selectOption(this.$refs.options[index].option, index)
      }
    },

    selectOption (option, index, options = { autoClose: true }) {
      const shouldSelect = this.multiple && !this.isOptionSelected(option)

      if (this.multiple) {
        this.updateOption(option, { select: shouldSelect })
      } else {
        this.setValue(option)
        this.selectedIndex = index
      }

      this.$emit('select', option, {
        selected: this.multiple ? shouldSelect : true
      })

      this.highlightedIndex = index
      this.clearQuery()

      if (!this.multiple && options.autoClose) {
        this.closeDropdown()
      }
    },

    isOptionSelected (option) {
      if (this.multiple) {
        return looseIndexOf(this.value, option) > -1
      }

      return looseEqual(this.value, option)
    },

    updateOption (option, options = { select: true }) {
      let value = []
      let updated = false
      const i = looseIndexOf(this.value, option)

      if (options.select && i < 0) {
        value = this.value.concat(option)
        updated = true
      }

      if (!options.select && i > -1) {
        value = this.value.slice(0, i).concat(this.value.slice(i + 1))
        updated = true
      }

      if (updated) {
        this.setValue(value)
      }
    },

    defaultFilter (option) {
      const query = this.query.toLowerCase()
      let text = option[this.keys.label] || option

      if (typeof text === 'string') {
        text = text.toLowerCase()
      }

      return fuzzysearch(query, text)
    },

    clearQuery () {
      this.query = ''
    },

    toggleDropdown () {
      this[this.showDropdown ? 'closeDropdown' : 'openDropdown']()
    },

    openDropdown () {
      if (this.disabled) {
        return
      }

      this.showDropdown = true

      // IE: clicking label doesn't focus the select element
      // to set isActive to true
      if (!this.isActive) {
        this.isActive = true
      }
    },

    closeDropdown (options = { autoBlur: false }) {
      this.showDropdown = false

      if (!this.isTouched) {
        this.isTouched = true
        this.$emit('touch')
      }

      if (options.autoBlur) {
        this.isActive = false
      } else {
        this.$refs.label.focus()
      }
    },

    onFocus (e) {
      if (this.isActive) {
        return
      }

      this.isActive = true
      this.$emit('focus', e)
    },

    onBlur (e) {
      this.isActive = false
      this.$emit('blur', e)

      if (this.showDropdown) {
        this.closeDropdown({ autoBlur: true })
      }
    },

    onOpen () {
      this.$nextTick(() => {
        this.$refs[this.hasSearch ? 'searchInput' : 'dropdown'].focus()
        this.scrollOptionIntoView(this.$refs.optionsList.querySelector('.is-selected'))
      })
    },

    onClose () {
      this.highlightedIndex = this.multiple ? -1 : this.selectedIndex
    },

    onExternalClick (e) {
      if (!this.$el.contains(e.target)) {
        if (this.showDropdown) {
          this.closeDropdown({ autoBlur: true })
        } else if (this.isActive) {
          this.isActive = false
        }
      }
    },

    scrollOptionIntoView (optionEl) {
      scrollIntoView(optionEl, {
        container: this.$refs.optionsList,
        marginTop: 180
      })
    },

    reset () {
      this.setValue(JSON.parse(this.initialValue))
      this.clearQuery()
      this.resetTouched()

      this.selectedIndex = -1
      this.highlightedIndex = -1
    },

    resetTouched (options = { touched: false }) {
      this.isTouched = options.touched
    }
  },

  components: {
    UiIcon,
    UiProgressCircular,
    UiSelectOption
  }
}
</script>

<style lang="scss">
@import './styles/imports';

.ui-select {
  align-items: flex-start;
  display: flex;
  font-family: $font-stack;
  margin-bottom: $ui-input-margin-bottom;
  outline: none;
  position: relative;

  &:hover:not(.is-disabled) {
    .ui-select__label-text {
      color: $ui-input-label-color--hover;
    }

    .ui-select__display {
      border-bottom-color: $ui-input-border-color--hover;
    }

    .ui-select__dropdown-button {
      color: $ui-input-button-color--hover;
    }
  }

  &.is-active:not(.is-disabled) {
    .ui-select__label-text,
    .ui-select__icon-wrapper .ui-icon {
      color: $ui-input-label-color--active;
    }

    .ui-select__display {
      border-bottom-color: $ui-input-border-color--active;
      border-bottom-width: $ui-input-border-width--active;
    }
  }

  &.has-floating-label {
    .ui-select__label-text {
      // Behaves like a block, but width is the width of its content.
      // Needed here so label doesn't overflow parent when scaled.
      display: table;

      &.is-inline {
        color: $ui-input-label-color; // So the hover styles don't override it
        cursor: pointer;
        transform: translateY($ui-input-label-top--inline) scale(1.1);
      }

      &.is-floating {
        transform: translateY(0) scale(1);
      }
    }
  }

  &.has-label {
    .ui-select__icon-wrapper {
      padding-top: $ui-input-icon-margin-top--with-label;
    }

    .ui-select__dropdown-button {
      top: $ui-input-button-margin-top--with-label;
    }
  }

  &:not(.is-multiple) {
    .ui-select__display {
      height: $ui-input-height;
      line-height: 1;
    }
  }

  &.is-multiple {
    .ui-select__display {
      line-height: 1.4;
      padding-bottom: rem-calc(4px);
      padding-top: rem-calc(4px);
    }
  }

  &.is-invalid:not(.is-disabled) {
    .ui-select__label-text,
    .ui-select__icon-wrapper .ui-icon {
      color: $ui-input-label-color--invalid;
    }

    .ui-select__display {
      border-bottom-color: $ui-input-border-color--invalid;
    }

    .ui-select__feedback {
      color: $ui-input-feedback-color--invalid;
    }
  }

  &.is-disabled {
    .ui-select__display {
      border-bottom-style: $ui-input-border-style--disabled;
      border-bottom-width: $ui-input-border-width--active;
      color: $ui-input-text-color--disabled;
      cursor: default;
    }

    .ui-select__dropdown-button,
    .ui-select__display-value.is-placeholder {
      color: $ui-input-text-color--disabled;
      opacity: $ui-input-button-opacity--disabled;
    }

    .ui-select__icon-wrapper .ui-icon {
      opacity: $ui-input-icon-opacity--disabled;
    }

    .ui-select__feedback {
      opacity: $ui-input-feedback-opacity--disabled;
    }
  }
}

.ui-select__label {
  display: block;
  margin: 0;
  outline: none;
  padding: 0;
  position: relative;
  width: 100%;
}

.ui-select__icon-wrapper {
  flex-shrink: 0;
  margin-right: $ui-input-icon-margin-right;
  padding-top: $ui-input-icon-margin-top;

  .ui-icon {
    color: $ui-input-icon-color;
  }
}

.ui-select__content {
  flex-grow: 1;
}

.ui-select__label-text {
  color: $ui-input-label-color;
  font-size: $ui-input-label-font-size;
  line-height: $ui-input-label-line-height;
  margin-bottom: $ui-input-label-margin-bottom;
  transform-origin: left;
  transition: color 0.1s ease, transform 0.2s ease;
}

.ui-select__display {
  align-items: center;
  border: none;
  border-bottom-color: $ui-input-border-color;
  border-bottom-style: solid;
  border-bottom-width: $ui-input-border-width;
  color: $ui-input-text-color;
  cursor: pointer;
  display: flex;
  font-family: $font-stack;
  font-size: $ui-input-text-font-size;
  font-weight: normal;
  padding: 0;
  transition: border 0.1s ease;
  user-select: none;
  width: 100%;
}

.ui-select__display-value {
  flex-grow: 1;

  &.is-placeholder {
    color: $hint-text-color;
  }
}

.ui-select__dropdown-button {
  color: $ui-input-button-color;
  font-size: $ui-input-button-size;
  margin-left: auto;
  margin-right: rem-calc(-4px);
}

.ui-select__dropdown {
  background-color: white;
  box-shadow: 1px 2px 8px $md-grey-600;
  color: $primary-text-color;
  display: block;
  list-style-type: none;
  margin: 0;
  margin-bottom: rem-calc(8px);
  min-width: rem-calc(180px);
  outline: none;
  padding: 0;
  position: absolute;
  width: 100%;
  z-index: $z-index-dropdown;
}

.ui-select__search-input {
  background: none;
  border: none;
  border-bottom-color: $ui-input-border-color;
  border-bottom-style: solid;
  border-bottom-width: $ui-input-border-width;
  border-radius: 0;
  color: $ui-input-text-color;
  cursor: auto;
  font-family: $font-stack;
  font-size: $ui-input-text-font-size - rem-calc(1px);
  font-weight: normal;
  height: $ui-input-height + rem-calc(4px);
  outline: none;
  padding: rem-calc(0 12px);
  padding-left: rem-calc(40px);
  transition: border 0.1s ease;
  width: 100%;

  // Hide Edge and IE input clear button
  &::-ms-clear {
    display: none;
  }

  &:focus + .ui-select__search-icon {
    color: $ui-input-label-color--active;
  }
}

.ui-select__search-icon,
.ui-select__search-progress {
  position: absolute;
  top: rem-calc(8px);
}

.ui-select__search-icon {
  color: $ui-input-icon-color;
  font-size: rem-calc(20px);
  left: rem-calc(12px);
}

.ui-select__search-progress {
  right: rem-calc(12px);
}

.ui-select__options {
  background-color: white;
  color: $primary-text-color;
  display: block;
  list-style-type: none;
  margin: 0;
  max-height: rem-calc(256px);
  min-width: 100%;
  overflow-y: auto;
  padding: 0;
  position: relative;
}

.ui-select__no-results {
  color: $secondary-text-color;
  font-size: rem-calc(14px);
  padding: rem-calc(8px 12px);
  width: 100%;
}

.ui-select__feedback {
  color: $ui-input-feedback-color;
  font-size: $ui-input-feedback-font-size;
  line-height: $ui-input-feedback-line-height;
  margin: 0;
  padding-top: $ui-input-feedback-padding-top;
  position: relative;
}

// ================================================
// Icon Positions
// ================================================

.ui-select--icon-position-right {
  .ui-select__icon-wrapper {
    margin-left: rem-calc(8px);
    margin-right: 0;
    order: 1;
  }
}

// ================================================
// Transitions
// ================================================

.ui-select--transition-fade-enter-active,
.ui-select--transition-fade-leave-active {
  transition: opacity 0.2s ease;
}

.ui-select--transition-fade-enter,
.ui-select--transition-fade-leave-active {
  opacity: 0;
}
</style>
